Physics
drorzel | May 28, 2014A little while back, I was put in touch with a Wall Street Journal writer who was looking into a new-ish health fad called "earthing," which involves people sleeping on special grounded mats and that sort of thing. The basis of this particular bit of quackery is the notion that spending time indoors, out of contact with the ground, allows us to pick up a net positive charge relative to the Earth, and this has negative health consequences. Walking barefoot on the ground, or sleeping on a pad that is electrically connected to ground via your house's wiring, allows you to replace your lost…
esiegel | May 27, 2014“Science casts a long black shadow back over who we think we are, and where it falls the temperature falls with it. Its touch is chilly and unforgiving.” -Richard K. Morgan
Here on Earth, when we're dealing with normal matter, it's relatively easy to measure the temperature of something. Even if you don't have a thermometer handy, if you can do something like measure the speed/kinetic motion of the particles in there, you can easily figure out what the temperature of a system is.
Image credit: screenshot from Schooltube, of a video by mrcoia (Teacher),L A Webber High School.
But things are…
esiegel | May 22, 2014“These neutrino observations are so exciting and significant that I think we’re about to see the birth of an entirely new branch of astronomy: neutrino astronomy.” -John Bahcall
From the Hubble expansion of the Universe to isotropy and homogeneity to the light elements to the leftover radiation glow to the formation of large-scale structure in the Universe, the Big Bang is by far the most successful scientific description of the Universe of all-time.
Image credit: Illustris Simulation, M. Vogelsberger, S. Genel, V. Springel, P. Torrey, D. Sijacki, D. Xu, G. Snyder, S. Bird, D. Nelson, L.…
drorzel | May 22, 2014That recent study on active learning continues to generate some press, including a new interview with Carl Wieman about why traditional lectures are problematic. Wieman is pretty blunt about his opinions on the subject, which will come as no surprise to people in the AMO physics community...
Anyway, while most of the rest of the academic nation is into final exams and even graduation parties, we still have two more weeks of class after this one, and we're giving an exam tonight in my intro E&M class. Which means I'm still spending a lot of time thinking about this stuff. Some related…
drorzel | May 21, 2014Rhett and I did the 15th episode of our Uncertain Dots hangout yesterday, commenting on a discussion started by Casey Rutherford about what we would like students coming into college physics to know. We had a slight difference of opinion about physics content, but agreed about the importance of algebra (which is like sunscreen).
I had meant to post this last night, but SteelyKid has made friends with the kids at one of the houses behind ours, so I spent a good chunk of the evening making sure she didn't climb over the fence into their yard. So, instead, you get to wake up with our physics…
drorzel | May 20, 2014While solo-parenting Sunday night, I still managed to get free of The Pip just barely in time to catch the start of Cosmos. This was a strange episode in a couple of ways, chiefly having to do with the selection of topics.
For one thing, there's no small irony in the fact that following a couple of weeks in which host Neil deGrasse Tyson has been raked over metaphorical coals for dismissing philosophy as pointless because it doesn't lead to testable predictions, a big chunk of the episode was given over to wildly impractical speculations about panspermia and related topics. I realize it's…
drorzel | May 19, 2014Every now and then, I run across a question in class that I genuinely don't know how to answer. If I'm lucky, this happens when I'm prepping a class, rather than when a student asks it live. Like today, when I noticed the above discussion question in my slides (reproduced at the bottom as well for those reading via RSS).
The discussion question itself is perfectly straightforward-- the current in the wire creates a magnetic field, the moving electron interacts with that, and getting the direction of the force is a straightforward right-hand-rule problem. I'll pose this to the class and ask…
catdynamics | May 15, 2014Senior Review is out:
summary - Swift #1, then NuStar.
K2 gets partial funding. Spitzer is terminated.
Panel recommends not cutting off the bottom but balancing fields.
NASA Response to the 2014 Senior Review for Astrophysics Operating Missions - Final Version for Release (5.16.14) - this is an edited update of the NASA response that was on the website on the 15th of May. It is tagged as Final version and for release, so I guess it is now official.
Final Report Astro 2014 Senior Review Panel (pdf)
NASA Response to 2014 Senior Review for Operating Missions FINAL (pdf)
NASA used the…
esiegel | May 15, 2014“Is your Hot Pocket cold in the middle?”
“It’s frozen. But it can be served boiling lava hot.”
“Will it burn my mouth?”
“It’ll destroy your mouth. Everything will taste like rubber for a month.” -Jim Gaffigan
You've all had the experience: you're all excited to microwave your favorite snack. So you pull it out of the freezer, you throw it in, and you let it rip. A minute or two later, you pull it out, and there it is: boiling on the outside, frozen in the middle. Welcome to the world of hot pockets.
Image credit: Wikimedia Commons user Tony Branston, via a C.C.-SA-2.0 license.
The…
drorzel | May 15, 2014A couple of weeks ago, io9 ran a piece about the old accusations that Robert Millikan manipulated his data for the electron charge with the headlineDid a Case of Scientific Misconduct Win the Nobel Prize for Physics? that got a lot of attention. I wasn't as impressed with this as a lot of other people, mostly because it's mostly just adding a clickbait headline to a story that's been around for decades, and doesn't even really engage with the various responses and defenses of Millikan, including this PDF that offers a (to my mind) fairly convincing argument that most of the argument turns on…
drorzel | May 14, 2014Over at Xykademiqz, a couple of weeks ago, there was a very nice post about the struggle to get students to write. "Very nice" here means that it's a good description of the problem, not that I'm glad anybody else has to deal with this.
I don't face quite the same thing-- my students generally aren't writing research papers for journals-- but getting senior theses written is often a bit of a chore. And I admit, I'm really bad about pushing students to do this in a systematic way. The problem is that, as I know from personal experience back when I was an undergrad and saber-tooth tigers…
esiegel | May 13, 2014“For my part I know nothing with any certainty, but the sight of the stars makes me dream.” -Vincent Van Gogh
Ever since the BICEP2 team reported their findings -- and evidence for B-mode polarization of the cosmic microwave background indicating gravitational waves from inflation -- the physics world has never been the same.
Images credit: Seljak & Zaldarriaga (L), Wayne Hu (R), viahttp://cosmology.berkeley.edu/~yuki/CMBpol/CMBpol.htm.
Recently, there have been rumors that perhaps this B-mode signal is due to the Milky Way, and not due to inflation after all. If this does turn out to…
drorzel | May 13, 2014Another week, another hangout with Rhett. In which we actually fielded a couple of questions from readers on Twitter, about the reason for inertia and a kind of meta-question. More audience questions would, of course, be welcome.
A couple of links to things that came up:
Mach's Principle, a past attempt to explain the origin of inertia.
Newton's famous refusal to explain gravity, "Hypotheses non fingo." Sir Isaac was second to none in his mastery of snotty condescension.
Veritasium's buoyancy quiz.
Aatish Bhatia's post about a new meta-analysis of "active learning" studies showing that…
drorzel | May 13, 2014I've been setting up schedules with my summer research students lately, and the main constraint we're facing with that is that I'm going to spend most of August in Europe. Part of this is pure vacation-- Kate and I are going to the UK for a couple of weeks. Part of it is the World Science Fiction Convention in London, in the middle of that trip, where both Kate and I expect to be on programming (though there aren't any set items this far out). And the last bit has just been officially announced: I'm speaking at the Nordita Workshop for Science Writers organized by Sabine Hossenfelder from…
drorzel | May 12, 2014Last night's episode of the Cosmos reboot focused on one of the three physicists whose pictures Einstein kept in his office: Michael Faraday. I'm a big fan of Faraday, who famously started his career as a bookbinder's apprentice reading the books brought into the shop, and ended as one of the greatest experimental physicists of the 19th Century. Also, he had magnificent sideburns, as you can see in the picture. It's a great story-- I highly recommend his biography-- and pretty much the entire episode was devoted to Faraday, with only a surprisingly tenuous astronomy connection at the end,…
drorzel | May 11, 2014Over at Five Thirty Eight, Walt Hickey has a piece about cheerleading as a sport and injury rates, which is both a nice look at the way to use stats to measure the real danger level of an activity, and the sort of small details that can be teased out. The piece includes a table of injury rates for a wide variety of sports, seen above as the "featured image" and reproduced below. I don't really have anything much to say about cheerleading, but one thing did jump out at me from the table, leading to the question in the post title.
this table show concussion rates in competition and in practice…
esiegel | May 9, 2014“Art has a way of confronting us, of reminding us, of engaging us, in what it means to be human, and what it means to be human is to be flawed, is to be contradictory, is to be often weak, and yet despite all of these what we would consider drawbacks, that we’re also quite beautiful. Spin is the opposite.” -Junot Diaz
"Two identical fermions cannot occupy the same state," says the Pauli Exclusion Principle, one of the most fundamental laws of quantum physics that governs our Universe. But if that's truly the case, then how can two hydrogen atoms bind together?
Image credit: New Scientist.…
drorzel | May 9, 2014Last weekend, the circus came to town, and Grandma and Grandpa came up to help us take the kids. We took SteelyKid a couple of years ago, and figured The Pip was old enough to go this time, too. Having bought tickets a couple of years ago, I got sent a pre-sale offer link, and followed that to get tickets in the front center section.
What I didn't realize was that these put us in the "Circus Celebrity" section-- when the show started, they came and gave us these ribbon things to wear, and a bit before the intermission some of the performers came over to our section, and led us out to the…
drorzel | May 8, 2014This coming fall term, I'll be teaching Astronomy 052, "Relativity, Black Holes, and Quasars," because the guy who has traditionally taught it (a radio astronomer who studies active galactic nuclei) has to do other courses instead. But I said "Well, hell, I've written a popular audience book explaining relativity. I can teach that." And since I get to make teaching assignments (the one and only positive feature of being department chair), well, I put myself down to teach it. Now, of course, I find myself thinking about ideas for that class, months in advance, when I ought to be working on…
drorzel | May 7, 2014I've seen a few links passed around to this Tom Siegfried post about science literacy, which is mostly a familiar story about how polls show most Americans giving incorrect answers to science questions. The sort of stuff you find in the NSF's Science and Engineering Indicators report. What's getting the social-media attention, though, is this paragraph near the end:
In fact, I’d contend (and have contended) that the problem with science education is not that it fails to inculcate enough facts, but that it tries to inculcate too many. Science classes in high school and intro classes in…